#!/usr/bin/perl
use strict;
use warnings;
#use diagnostics;
use Data::Dumper;
use IO::Socket::INET;
use POSIX qw( CLOCKS_PER_SEC );
use Time::HiRes qw( gettimeofday CLOCK_REALTIME clock_getres );

use constant TRUE      => scalar 1;
use constant ARGUMENTS => scalar 1;
use constant MAXBYTES  => scalar 512;
use constant MAX_PORT  => scalar 65536;
use constant MIN_PORT  => scalar 1;

my $dot = ".";
my $rcvSntpPacket;

if ( @ARGV > ARGUMENTS ) {
    print "\nPlease no more than ".ARGUMENTS." argument input!\n";
    print "\nCorrect Syntax: perl $0 IP:PORT (e.g. 127.0.0.1:12345)\n"
+;
    exit(0);
}
elsif ( @ARGV < ARGUMENTS ) {
    print "\nPlease no less than ".ARGUMENTS." argument input!\n";
    print "\nCorrect Syntax: perl $0 IP:PORT (e.g. 127.0.0.1:12345)\n"
+;
    exit(0);
}
else {

    my $info = $ARGV[0]; # User input IP:PORT;

    my $string = index($info, ':');

    if ($string == '-1') {
    die "Please include ':' in between the IP and Port - ".$info."\n";
    }

    my @input = split( ':' , $info );

    die "\nPlease use PORT number between ".MIN_PORT." - ".MAX_PORT."\
+n\n" 
    if ( ( $input[1] > MAX_PORT ) || ( $input[1] < MIN_PORT ) );

    my $client_socket = new IO::Socket::INET (
    PeerHost => $input[0],
    Type     => SOCK_DGRAM,
    PeerPort => $input[1], # Default NTP port 123, due to permission d
+enied switch to client set
    Proto    => 'udp'
    ) or die "ERROR in Socket Creation: $@\n";

    my $Peer_Port = $client_socket->peerport();

    my $client_li_vm_mode = '00100011'; # 8 bit
    my $client_stratum = '0'; # 8 bit
    my $client_poll = '0'; # 8 bit
    my $client_precision = '0'; # 8 bit
    my $client_root_delay = '0'; # 32 bit
    my $client_dispersion = '0'; # 32 bit
    my $client_reference_identifier = '0'; # 32 bit
    my $client_reference_timestamp_sec = '0'; # 32 bit
    my $client_reference_timestamp_microsec = '0'; # 32 bit
    my $client_receive_timestamp_sec = '0'; # 32 bit
    my $client_receive_timestamp_microsec = '0'; # 32 bit

    my ( $client_transmit_sec , $client_transmit_microsec ) = gettimeo
+fday(); # 64 bit

    my $client_originate_timestamp_sec = $client_transmit_sec;
    my $client_originate_timestamp_microsec = $client_transmit_microse
+c;

    my @arraySendSntpPacket = ($client_li_vm_mode , $client_stratum , 
+$client_poll , $client_precision , $client_root_delay , $client_dispe
+rsion , $client_reference_identifier , $client_reference_timestamp_se
+c , $client_reference_timestamp_microsec , $client_originate_timestam
+p_sec , $client_originate_timestamp_microsec , $client_receive_timest
+amp_sec , $client_receive_timestamp_microsec , $client_transmit_sec ,
+ $client_transmit_microsec );

    warn Dumper \@arraySendSntpPacket;

    my $sendSntpPacket = pack "B8 C3 N11", @arraySendSntpPacket;

    $client_socket->send( $sendSntpPacket ) 
    or die "Client error while send: $!\n";

    $client_socket->recv( $rcvSntpPacket , MAXBYTES )
    or die "Client error while received: $!\n";

    my ( $client_rcv_sec , $client_rcv_microsec ) = gettimeofday();

    $client_socket->close(); # Close socket()

    my @arrayRcvSntpPacket = unpack("B8 C3 N11" , $rcvSntpPacket);

    my ( $server_li_vm_mode , $server_stratum , $server_poll_interval 
+, $server_precision , $server_root_delay , $server_dispersion , $serv
+er_reference_identifier , $server_reference_timestamp_sec , $server_r
+eference_timestamp_microsec , $server_originate_timestamp_sec , $serv
+er_originate_timestamp_microsec , $server_rcv_timestamp_sec , $server
+_rcv_timestamp_microsec , $server_transmit_timestamp_sec , $server_tr
+ansmit_timestamp_microsec ) = @arrayRcvSntpPacket;

    warn Dumper \@arrayRcvSntpPacket;

} # End of else ARGV provided
[download]

#!/usr/bin/perl
use strict;
use warnings;
use IO::Socket::INET;
use Time::HiRes qw( gettimeofday );

use constant TRUE       => scalar 1;
use constant ARGUMENTS  => scalar 1;
use constant MAXBYTES   => scalar 512;
use constant MAX_PORT   => scalar 65536;
use constant MIN_PORT   => scalar 1;
use constant UNIX_EPOCH => 2208988800;

my $unpack_ip = sub {
    my $ip;
    my $stratum = shift;
    my $tmp_ip = shift;
    if($stratum < 2){
    $ip = unpack("A4", 
             pack("H8", $tmp_ip)
            );
    }else{
    $ip = sprintf("%d.%d.%d.%d",
              unpack("C4",
                 pack("H8", $tmp_ip)
              )
            );
    }
    return $ip;
};

my $frac2bin = sub {
    my $bin  = '';
    my $frac = shift;
    while ( length($bin) < 32 ) {
    $bin  = $bin . int( $frac * 2 );
    $frac = ( $frac * 2 ) - ( int( $frac * 2 ) );
    }
    return $bin;
};

my $bin2frac = sub {
    my @bin = split '', shift;
    my $frac = 0;
    while (@bin) {
    $frac = ( $frac + pop @bin ) / 2;
    }
    return $frac;
};

my $dot = ".";
my $rcvSntpPacket;
my $serverPrecision;

my $info = $ARGV[0]; # User input IP:PORT;

my $string = index($info, ':');

if ($string == '-1') {
    die "Please include ':' in between the IP and Port - ".$info."\n";
}

my @input = split( ':' , $info );

my $client_socket = new IO::Socket::INET (
    PeerHost => $input[0],
    Type     => SOCK_DGRAM,
    PeerPort => $input[1],
    Proto    => 'udp'
    ) or die "ERROR in Socket Creation: $@\n";

my $Peer_Port = $client_socket->peerport();

my $client_li_vn_mode = '00100011'; # 8 bit
my $client_stratum = '0'; # 8 bit
my $client_poll = '0'; # 8 bit
my $client_precision = '0'; # 8 bit
my $client_root_delay = '0'; # 32 bit
my $client_dispersion = '0'; # 32 bit
my $client_reference_identifier = '0'; # 32 bit
my $client_reference_timestamp_sec = '0'; # 32 bit
my $client_reference_timestamp_microsec = '0'; # 32 bit
my $client_originate_timestamp_sec = 0; # 32 bit
my $client_originate_timestamp_microsec = 0; # 32 bit
my $client_receive_timestamp_sec = '0'; # 32 bit
my $client_receive_timestamp_microsec = '0'; # 32 bit

my ($client_transmit_sec , $client_transmit_microsec) = gettimeofday()
+;
my $client_transmit_timestamp = $client_transmit_sec . $dot . $client_
+transmit_microsec;

my @arraySendSntpPacket = ($client_li_vn_mode , $client_stratum , $cli
+ent_poll , $client_precision , $client_root_delay , $client_dispersio
+n , $client_reference_identifier , $client_reference_timestamp_sec , 
+$client_reference_timestamp_microsec , $client_originate_timestamp_se
+c , $client_originate_timestamp_microsec , $client_receive_timestamp_
+sec , $client_receive_timestamp_microsec , $client_transmit_sec , $cl
+ient_transmit_microsec );

my $sendSntpPacket = pack "B8 C3 N10 B32", @arraySendSntpPacket;

$client_socket->send( $sendSntpPacket ) 
    or die "Client error while send: $!\n";

$client_socket->recv( $rcvSntpPacket , MAXBYTES )
    or die "Client error while received: $!\n";

my ($client_rcv_sec , $client_rcv_microsec) = gettimeofday();
my $client_rcv_timestamp = $client_rcv_sec . $dot . $client_rcv_micros
+ec;

$client_socket->close(); # Close socket()

my @arrayRcvSntpPacket = unpack("a C3   n B16 n B16 H8   N B32 N B32  
+ N B32 N B32" , $rcvSntpPacket);

my ( $server_li_vm_mode , $server_stratum , $server_poll_interval , $s
+erver_precision , $server_root_delay_sec , $server_root_delay_microse
+c , $server_dispersion_sec , $server_dispersion_microsec , $server_re
+ference_identifier , $server_reference_timestamp_sec , $server_refere
+nce_timestamp_microsec , $server_originate_timestamp_sec , $server_or
+iginate_timestamp_microsec , $server_rcv_timestamp_sec , $server_rcv_
+timestamp_microsec , $server_transmit_timestamp_sec , $server_transmi
+t_timestamp_microsec ) = @arrayRcvSntpPacket;

my @serverLiVnMode = ((unpack( "C", $server_li_vm_mode & "\xC0" ) >> 6
+),
              (unpack( "C", $server_li_vm_mode & "\x38" ) >> 3),
              (unpack( "C", $server_li_vm_mode & "\x07" )));

my $serverPoll = (sprintf("%0.1d", $server_poll_interval));

if ($server_precision < 127) {
    $server_precision = 0;
}
else {
    $server_precision = $server_precision - 255;
}

my $serverRootDelay = ($bin2frac -> ($server_root_delay_microsec));
my $serverDispersionSeconds = sprintf("%0.10f", $server_dispersion_sec
+);
$serverDispersionSeconds =~ s/\..*$//;
my $serverDispersionFinalSeconds = $bin2frac->($serverDispersionSecond
+s);
my $serverDispersionMicroSeconds = sprintf("%0.10f", $server_dispersio
+n_microsec);
$serverDispersionMicroSeconds =~ s/\..*$//;
my $serverDispersionFinalMicroSeconds = $bin2frac->($serverDispersionM
+icroSeconds);
my $serverReferenceIdentifier = $unpack_ip->($server_stratum,$server_r
+eference_identifier);
(($server_reference_timestamp_sec += $bin2frac->($server_reference_tim
+estamp_microsec)) -= UNIX_EPOCH);
($server_originate_timestamp_sec += $bin2frac->($server_originate_time
+stamp_microsec));
(($server_rcv_timestamp_sec += $bin2frac->($server_rcv_timestamp_micro
+sec)) -= UNIX_EPOCH);
(($server_transmit_timestamp_sec += $bin2frac->($server_transmit_times
+tamp_microsec)) -= UNIX_EPOCH);

# RFC2030 reference https://tools.ietf.org/html/rfc4330
my $d = ( ( $client_rcv_timestamp -  $client_transmit_timestamp ) - ( 
+$server_rcv_timestamp_sec - $server_transmit_timestamp_sec ) );
my $t = ( ( ( $server_rcv_timestamp_sec -  $client_transmit_timestamp 
+) + ( $server_transmit_timestamp_sec - $client_rcv_timestamp ) ) / 2 
+);

# Clear screen for viewing the output
system $^O eq 'MSWin32' ? 'cls' : 'clear';

print "Round Trip delay: ".$d."\n";
print "Clock offset: ".$t."\n";
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